Tubular slat for coverings for architectural openings

ABSTRACT

A slat or vane for use in a covering for an architectural opening is suitable for use in either a horizontal or vertical orientation and in a horizontal orientation will not sag or droop, and in a vertical orientation will rotate uniformly along its length when rotated from end thereof. The slat is formed in a tubular configuration and has a base material of glass fibers bonded together in a thermoformable resin so as to maintain the arcuate curvature desired for the tubular slat or vane. The slat can be repeatedly deformed and will always return to its original configuration.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.10/332,411 filed on 7 Jan. 2003 entitled “Tubular Slat for Coverings forArchitectural Openings”, which application is the Section 371(c) filingof International Application No. PCT/US01/22336 with an internationalfiling date of 16 Jul. 2001 entitled “Tubular Slat for Coverings forArchitectural Openings”, which claims priority under 35 U.S.C. §119(e)to U.S. provisional application No. 60/219,039 filed on 18 Jul. 2000 andentitled “Tubular Slat for Coverings for Architectural Openings”, all ofwhich are incorporated by reference as if fully described herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to slats for use in horizontalor vertical coverings for architectural openings and, more particularly,to such a slat that has been formed in a transversely compressibletubular configuration.

2. Description of the Relevant Art

Coverings for architectural openings have been in use for centuries andhave assumed many different forms. For years fabrics were simply drapedacross architectural openings such as windows, doors, archways and thelike, but subsequently more sophisticated coverings have emerged. Forexample, pleated draperies have been in use for some time and can bemoved with conventional hardware between an extended position across anarchitectural opening and a retracted position adjacent the sides of theopening.

Another popular form of covering is a Venetian blind which consists of aplurality of horizontally disposed wooden or aluminum slats and, morerecently, plastic slats that are supported at spaced locations alongtheir length by ladders. The ladders, which may be tape ladders or cordladders, consist of parallel but spaced vertically extending flexiblefabric tapes or cords having a plurality of slat supportingcross-ladders or rungs extending therebetween at vertically spacedlocations. The slats are supported on the cross-ladders. Lift cordsextend vertically through the slats and appropriate control mechanismsare provided so that the lift cords can be raised thereby gathering oraccumulating the slats into a stacked relationship when the covering ismoved from an extended position across the architectural opening to aretracted position adjacent the top of the architectural opening.Further, by shifting the parallel tapes, cables or cords of the laddersin opposite vertical directions, the cross-ladders are tilted therebytilting the slats so as to move the Venetian blind between open andclosed positions to selectively permit the passage of vision and lightbetween the slats.

More recently, coverings for architectural openings have includedvertical blinds which are similar to Venetian blinds except the slatsare disposed vertically rather than horizontally. Like Venetian blinds,the slats can be pivoted about their longitudinal axes to move thecovering between open and closed positions. The slats, as a group, canalso be extended or retracted across the architectural opening.

Even more recently, designer coverings for architectural openings haveincluded cellular blinds wherein interconnected cells of material extendacross the architectural opening and can be collapsed upon themselveswhen opening or closing the covering or moving it between extended andretracted positions.

While slats or vanes that are used in Venetian blinds or vertical blindshave traditionally been made of a rigid hard material, attempts havebeen made at softening the appearance of such slats or vanes, withexamples of such being disclosed in U.S. Pat. Nos. 5,797,442, 5,960,850and 5,876,545, which are commonly owned with the present application. Inthe aforenoted patents, the vanes have been suspended vertically andformed in a tubular configuration, with the tubular configurationsubstantially eliminating torque along the length of the vane so thatwhen the vane is rotated at its upper end by a control mechanism, thelower end of the vane will move in unison therewith. A characteristic ofthe tubular vanes in the aforenoted patents, however, is that they areeasily bendable along their length so that if disposed horizontally,they will droop or bend.

While tubular vanes have been employed in Venetian blinds, they havesuffered from various drawbacks.

There is a need in the art of coverings for architectural openings for atubular slat or vane that presents a softer appearance than hard wood,plastic or aluminum slats and the like, but which will also retain itsshape whether or not disposed horizontally or vertically. Furthermore,there is a need for slats that have a high degree of translucency,wherein a maximum amount of diffused light is transmitted through theshade.

SUMMARY OF THE INVENTION

The present invention concerns a tubular slat or vane that can be usedin horizontal or vertical coverings for architectural openings andwherein the vane presents a soft fabric appearance while retainingstructural rigidity along its length. The vane can, therefore, be usedin Venetian blinds or vertical blinds and when used in a Venetian blindwill not noticeably sag along its length, and when used in a verticalblind will rotate uniformly along its length without helically twisting.

The tubular vane can be made from various combinations of materials butin the preferred embodiments, the base structural component of thematerial is a fiberglass matting wherein the fibers might be woven,non-woven or randomly oriented but united with a thermoformable resin sothat the matting has deformable memory. In other words, it can be formedunder the application of heat into any desired configuration which itwill yieldingly maintain. It is resilient so as to always return to thatconfiguration even after having been temporarily deformed.

Preferably, but not necessarily, the fiberglass matting has a layer ofadditional fabric or other material which is either laminated to orwrapped over the fiberglass matting to give the slat the desired textureand/or aesthetic appearance, but the fiberglass matting will present andretain the structural qualities desired for the slat so that they willwithstand extreme environments which the slats encounter during shipmentand use such as the compression and deformation of the slats.

While the slats are formed into a tubular configuration, there are anumber of tubular configurations available.

Other aspects, features and details of the present invention can be morecompletely understood by reference to the following detailed descriptionof the preferred embodiments, taken in conjunction with the drawings andfrom the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary isometric view of a slat formed in accordancewith the present invention looking downwardly on the slat.

FIG. 2 is a fragmentary isometric similar to FIG. 1 but looking upwardlyat the slat.

FIG. 3 is an end elevation of the slat shown in FIGS. 1 and 2.

FIG. 4 is an isometric view of the vane shown in FIGS. 1 and 2 withparts thereof removed for clarity.

FIG. 5 is an isometric view of a Venetian blind incorporating the slatof the present invention and with the blind in an open and extendedposition.

FIG. 6 is an enlarged end elevation of the blind as shown in FIG. 5.

FIG. 7 is a further enlarged fragmentary end elevation of a portion ofthe blind shown in FIG. 6.

FIG. 8 is a fragmentary end elevation of the blind of FIG. 5 with theslats rotated into a closed position.

FIG. 9 is an end elevation similar to FIG. 6 which has been furtherenlarged and with parts removed for clarity and with the slats shown inan open position.

FIG. 10 is an end elevation similar to FIG. 9 with parts removed forclarity and with the slats in a closed position.

FIG. 11 is an end elevation of the blind of FIG. 5 with parts removedfor clarity and with the blind in a retracted position.

FIG. 12 is an enlarged end elevation of a plurality of slats inaccordance with the present invention shown supported by a cord ladderand with the slats in a retracted position.

FIG. 13 is a diagrammatic view of a process for forming the materialfrom which a slat can be formed.

FIG. 14 is an enlarged diagrammatic section taken along line 14-14 ofFIG. 13.

FIG. 15 is an enlarged diagrammatic section taken along line 15-15 ofFIG. 13.

FIG. 16 is a diagrammatic view of a second system for forming thematerial from which a slat can be made.

FIG. 17 is an enlarged diagrammatic section taken along line 17-17 ofFIG. 16.

FIG. 18 is an end elevation of the material from which a slat can beformed after the material has been assembled according to the apparatusshown in FIG. 13 or 16.

FIG. 19 is a diagrammatic end elevation showing a system for creasingthe material from which a slat is to be formed.

FIG. 20 is a diagrammatic end elevation showing a portion of theapparatus for preparing the slat material for formation into a tubularslat.

FIG. 21 is an end elevation of the slat material having a line ofadhesive formed along one edge and with crease lines having been placedtherein.

FIG. 22 is an enlarged end elevation of a slat formed with the strip ofmaterial illustrated in FIG. 21.

FIG. 23 is an end elevation of a strip of material from which a vane canbe formed with the material having an adhesive strip on the oppositeside from that shown in FIG. 21.

FIG. 24 is an enlarged view of a second embodiment of a slat formed fromthe strip of material shown in FIG. 23.

FIG. 25 is a fragmentary isometric view with parts removed of a controlsystem for a vertical vane covering for architectural openings whereinthe vanes have been formed in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The slat or vane 30 for use in a covering for an architectural openingin accordance with the present invention is probably seen best in FIGS.1-4 to comprise an elongated tubular body 32 having upper and loweroutwardly convex side walls 34 and 36, respectively, a folded edge 38and a secured edge 40. As will be described in more detail later, theslat is formed from a strip of material having opposite ends by foldingthe material longitudinally along a line proximate the centerline of thestrip and securing the free ends together in overlapping relationship.The slat can be cut to any desired length either before or afterformation of the tube. An important feature of the invention resides inthe material from which the vane is made inasmuch as it is desired thatthe slat, under normal use conditions, maintains its tubularconfiguration and is capable of returning to that tubular configurationeven after having been deformed or transversely compressed such as inextreme environments encountered in shipment and day-to-day use inarchitectural openings. An important component of the material is afiberglass web which can be woven, non-woven or composed of randomlyoriented glass fibers which are held together in a suitable resin. Thepreferred glass material is manufactured by Ahlstrom of Karhula, Finlandand designated as product #GFT-51G10-50. It is a non-woven glass fibertissue that has weight of 50 grams per square meter. In one embodiment,a thermoset resin is added to the glass non-woven at the time ofmanufacture at a level of 21 to 24% by dry weight. It is to beappreciated that high or lower amounts of resin can be utilizeddepending on the properties of the resin and the fiberglass. This resinwhich is added to the glass mat is only dried at the point ofmanufacturing. This allows the subsequent user the ability to place theglass tissue within a form and heat it to its cross-linking temperatureand dwell time. After the heating process, the resulting glass mat andthermosetting resin construction will maintain its shape indefinitely.The diameter of the glass fibers within the tissue is extremely small(11 microns). Along with its optical clarity, the glass fibers give theglass tissue, when observed with transmitted light, the desired amountof translucency as compared with other textile fibers which arerelatively opaque when observed in the same condition of transmittedlight. The thermosetting resin used to bind the glass fibers is athermoformable resin so that the orientation of the fibers and thematerial in which they are disposed remain somewhat constant, eventhough flexible, until the set orientation is modified or changed byheating the material to a predetermined temperature in excess of thesetting temperature of the resin. In other words, the fiberglassmaterial formed with the thermoformable resin can be heated to apredetermined temperature and then molded into a predeterminedconfiguration and after cooling will retain that configuration.

While a slat 30 made from such a fiberglass material can be formedsolely from the matting of fiberglass and resin, for aesthetic or otherreasons, it may be desirable to laminate a different material to thefiberglass matting. Materials such as most any fabric, foil or the likecan be laminated to the fiberglass material so that once the vane isformed, the different material, located on the exterior or interiorsurfaces of the tubular slat, gives the slat or the vane a desiredappearance.

As can be seen in FIGS. 1-4, slat 30 has a flap or external tail portion142, wherein the walls 34 and 36 are secured together to form the slat.In an alternative embodiment slat 144 as best shown in FIG. 24, noexternal tail portion is produced. In the alternative slat 144, one edgeof one of the walls is folded inwardly to meet the inside surface of theother wall, wherein the folded in portion is adhesively joined to thecorresponding inside surface.

With reference to FIGS. 5-11, the slat 30 is shown incorporated into aVenetian blind-type covering 42 for an architectural opening wherein theVenetian blind has a headrail 44 in which the control system for theblind is disposed, a lift cord 46, a tilt wand 48, a bottom rail 50spaced from but parallel to the headrail and cord ladders 52 at oppositeends of the blind. Each tubular slat 30 has been provided with alignedopenings 54 in the side walls thereof adjacent to the ends of the slatsso as to accommodate the incorporation of the slats into the blindsystem. The cord ladders, as probably best seen in FIGS. 6-8, have twovertically extending spaced tilt cords 56 with horizontal rungs 58connecting the tilt cords at equal vertically spaced locations. Eachrung supports an end of a slat so that the slats are disposed in aparallel horizontal orientation. The lift cords 46 extend through thevertically aligned openings 54 at the ends of each slat and are knottedor otherwise affixed at 62 beneath the base rail as best seen in FIGS.6-11. As seen in FIG. 12, when the blind is retracted, the vertical tiltcords 56 are folded along opposite edges of the slats with the rungs 58of each cord ladder extending between slats. In the retracted positionof FIG. 12, the slats can be seen to still be tubular, but they arecompressed into a very shallow tube so as to occupy minimal space. Inthat manner, the slats can be compressed into a very small space, whichis actually smaller than the space occupied by wooden slatsconventionally found in Venetian blinds.

Slats 30 can also be used in other types of Venetian blinds that utilizea lift cord that extends along the outside of the blinds, typicallyinterwoven with the vertical portion of the cord ladder. In this type ofVenetian blind, no openings need be made in the surface of the slat thatcan allow light to pass unimpeded therethrough when the blind is in theclosed position. It is appreciated that these slats may also becompressed when the blind is retracted in a similar manner asillustrated in FIG. 12. The use of the tubular slats with external liftcords are described in greater detail in the following U.S. patent andU.S. patent applications owned by assignee of the present application:U.S. Pat. No. 6,662,851 entitled “Ladder Operated Covering With FixedVanes For Architectural Openings”, and co-pending U.S. patentapplication Ser. No. 10/678,675, filed on 3 Oct. 2003 (Pub. No. U.S.2004/0065418 A1) entitled “Ladder Operated Covering With Fixed Vanes ForArchitectural Openings”, and U.S. application Ser. No. 10/479,893 filedon 1 Dec. 2003 (Pub. No. U.S. 2005/0072088 A1) entitled “Shutter TypeCovering For Architectural Openings”, all of which are incorporatedherein by reference in their entirety.

As mentioned previously, the fiberglass/resin matting material used inthe slats can be used alone, but for aesthetic or other reasons, aseparate material can be laminated to the base fiberglass/resin materialor wrapped around the base material. With reference to FIG. 13, aforming apparatus 64 and process for forming a strip material from whichthe slats 30 can be formed is illustrated. At one end of the apparatus,a supply roll 66 of a long strip of fiberglass/resin matting 68 isprovided with the matting having a width substantially double that ofthe width of the proposed slat to be made from the material. The stripof fiberglass matting is positioned beneath a second roll 70 of anelongated strip of fabric or other material 72 which is to be laminatedto the fiberglass matting 68. Free ends of the rolls of fiberglass andfabric strips are passed between a pair of confronting compressionrollers 74 after a layer of adhesive has been applied to the top surfaceof the fiberglass matting with a conventional adhesive applicator 76.The adhesive could be any suitable adhesive having properties such as athermoplastic or thermoset adhesive which tack bonds the fiberglassmaterial 68 to the fabric material 72 as they are passed between therollers 74. In one embodiment, no additional adhesive is applied withthe thermoformable adhesive of the fiberglass matting being utilized totack bond the fabric to the matting. Upon leaving the compressionrollers, the laminate 75 is drawn over a first heated mandril 78, whichcould be steel, aluminum or any suitable material, having longitudinallyextending passages 80 therein adjacent to an arcuate upper surface 82thereof. Heating fluids are passed through the passages to maintain thearcuate upper surface at a predetermined temperature in excess of thesetting temperature of the thermoformable resin used in the fiberglassmaterial and the adhesive 76. A section taken through the mandril 78with the laminate thereon is seen in FIG. 15. As the material is drawnacross the heated mandril, the thermoformable resin in the fiberglassmaterial is rendered fluid so that the cross-direction of the laminateassumes the arcuate configuration of the top surface 82 of the mandril.The laminate 75 leaving the downstream end of the heated mandril 78crosses over a cooling mandril 84 of the same structure as the heatingmandril except that in the cooling mandril coolant is passed throughlongitudinal passages (not shown) to retain the arcuate top surface 88of the cooling mandril at a preselected temperature beneath that of theheating mandril and such as to set the thermoformable resin. Thelaminate leaving the downstream end of the cooling mandril is,therefore, configured in a transverse arcuate shape and is passed aroundan idler roller 90 onto a take-up roller 92 where a predetermined lengthof the arcuate laminate strip is accumulated. While the cross-sectionalconfiguration of the laminate may be temporarily deformed on the take-uproller 92, once the strip of laminate material is removed from theroller, it will again assume the arcuate configuration it had before itwas wrapped onto the take-up roller.

With reference to FIGS. 16 and 17, an alternative system 94 for formingthe laminate strip 75 of material from which the slats can be formed isillustrated. As seen in FIG. 16, a strip roll 96 of fiberglass/resinmaterial is disposed beneath a strip roll 98 of a fabric or other chosenmaterial and a conventional adhesive applicator 100 is positionedtherebetween to dispense a layer of adhesive onto the top surface of thefiberglass/resin material. Again, the adhesive could be any suitableadhesive but preferably a thermoplastic adhesive. A pair of upper andlower endless belts 102 and 104, respectively, are positioned downstreamfrom the supply rolls of fiberglass and fabric with the endless beltsbeing wrapped around driven 106 and idler 108 rollers in a conventionalmanner. Positioned between the upper and lower endless belts is aheating mandril 110 and a downstream cooling mandril 112, each mandrilhaving an upper component 110 a, 112 a respectively and a lowercomponent 110 b, 112 b respectively. The confronting faces of the uppercomponents and lower components are convex and concave respectively andare spaced a predetermined distance to allow the free passage of thelaminate therebetween. The upper component 110 a, 112 a of the heatingand cooling mandrils, respectively, have elongated passages 114 adjacentto the convex surface thereof for the passage of heating and coolingfluids respectively so that the adjacent convex surfaces of the mandrilsare retained at predetermined temperatures. As the laminate is passedbetween the upper and lower mandril components of the heating mandril110, it is confined in an arcuate configuration and the temperaturereaches a temperature that cross links the thermoset resin. An optimumtemperature/time duration is believed to be approximately 410 degress F.for one minute with the Ahlstrom glass material identified above. Thatsame arcuate configuration is maintained in the laminate as it passesthrough the cooling mandril 112 where the temperature is dropped beneaththe temperature in the heating mandril which retains the arcuatetransverse cross-sectional configuration of the laminate 75 as it leavesthe downstream end of the cooling mandril and is wrapped onto a take-uproller 116. As mentioned with regard to the system illustrated in FIG.13, while the transverse cross-sectional configuration of the laminate75 might be deformed or changed temporarily while on the take-up roller,once it is unrolled, it will again assume the arcuate configurationimparted thereto as it passed through the heating and cooling mandrils.

FIGS. 18-22 illustrate how the arcuate laminate 75 is formed into thetubular slat. In FIG. 18, the arcuate laminate is shown in an end viewin the same arcuate configuration it has after leaving the coolingmandril 112 of the forming apparatus of either FIG. 13 or 16. Thelaminate strip is first passed through a creasing apparatus 118 asillustrated in FIG. 19. In passing through the creasing apparatus, thestrip of material is temporarily flattened so as to lie above and belowa pair of juxtaposed anvils 120 and between the anvils and creasingrollers 122 which have been positioned at predetermined locationsrelative to the strip. The locations of the creasing rollers aredetermined by where the laminate strip 75 will ultimately be folded intothe desired tubular configuration. In the disclosed embodiment of theslats, as will be appreciated in FIG. 19, one crease 124 is positionedat approximately the longitudinal center of the strip on one face of thestrip while another crease 126 is placed adjacent to one side edge ofthe strip on the opposite face. It is not critically important on whichside of the strip the creases are placed, but it has been found easierto crease the material while in a flat configuration, and in order toaccomplish such, it is relatively simply to run the laminate stripbetween the anvils and crease rollers as illustrated.

After having been creased, and as illustrated in FIG. 20, the laminatestrip 75 is passed through an adhesive application device 128 whichincludes a pair of confronting rollers 130 which are spaced an adequatedistance apart to allow the laminate strip to pass therebetween. Theupper roller is shorter than the lower roller to allow space for aconventional adhesive applicator 132 which applies a strip of adhesive133 to the top surface of the laminate strip between the crease 126 andthe right edge 134 of the strip. The adhesive could be any suitableadhesive but preferably a thermoplastic copolyester adhesive such asBostik 7183 made by Bostik Adhesives of Boston, Mass., or Griltex 6Gmade by EMS of Switzerland.

With reference to FIG. 21, after the laminate strip 75 emerges from theadhesive applicator, it again assumes its arcuate transverseconfiguration and it can then be passed through a folding mechanism (notshown) which takes the strip and folds it longitudinally along thecrease 124 at the approximate longitudinal center of the strip so thatthe edges 134 and 138 of the strip are in overlying confrontingrelationship with the adhesive 133 therebetween. While the strip 75 isbeing folded along the approximate longitudinal centerline thereof, aflap 140 is formed by folding the edge 134 of the strip with theadhesive thereon about its associated crease 126 so that when the sideedges of the laminate strip are in confronting relationship, the topwall 36 (which is shown on the bottom in FIG. 22) of the slat so formedretains it arcuate configuration and the flap 140 on the free edge ofthe bottom wall 34 (which is shown on the top in FIG. 22) of the slatconforms to the curvature of the top wall. At the location where theedges of the laminate strip are adhesively bonded, an external tail 142is formed which can be passed through a heat setting apparatus (notshown) to secure the edges of the laminate strip thereby permanentlyforming the slat into the tubular configuration shown in FIG. 22.

In an alternative embodiment 144 of the slat shown in FIG. 24, it isformed in a similar manner except that adhesive 146 (FIG. 23) is appliedto the undersurface 148 of the laminate strip 75 between the right edge148 of the strip and an adjacent crease line 150 and once the laminatestrip has been folded about a crease 152 running substantially along thelongitudinal center of the strip, a flap 154 defined between the rightedge 148 of the strip and the adjacent crease line 150 can be foldedinwardly to confront the top surface of the bottom wall 152 of the slatand, again, this location of the slat can be passed through a heatsetting apparatus (not shown) to secure the free edges of the laminatestrip together internally of the slat thereby forming a slat that doesnot have an external tail as in the slat of FIG. 22.

In FIG. 25, the slats 30 configured and as illustrated in FIG. 22 areshown disposed vertically in a vertical slat covering 156 for anarchitectural opening, the slats being suspended from a controlmechanism 158 that is adapted to shift the slats longitudinally of aheadrail 160 to extend or retract the covering and also rotate the slatsabout longitudinal vertical axes when opening or closing the covering. Avertical tab 162 has been formed in the end of the vane but in reality,it would be easiest to form the tab by adhesively securing a separatetab strip (not shown) to the open end of the tubular slat rather thanforming the tab in the laminate strip from which the slat is formed.

Because of the optical properties of the fiberglass material, theresulting slats 30 or 144 are typically translucent. When a windowcovering using these slats is placed in its closed position, shadowlines are not produced on adjacent slats caused by the overlapping slatas the slats diffuse the light passing therethrough. Additionally, sincethe slats are hollow, as well as translucent, patterned and/or coloredinserts can be inserted into the slats to change the resultingappearance of the slats as well as the slats level of translucency. Inone type of window blind assembly, wherein the slats are used in windowcoverings in which the lift and ladder cords are routed outside of thevanes and do not pass through the vanes, the appearance changing insertscan be easily installed post production by consumers or window coveringvendors.

A slat 30 or 144 formed in accordance with the present invention willnot sag or droop noticeably along its length even when disposedhorizontally and when provided in lengths commonly found in coveringsfor architectural openings due in large part to the tubular constructionand the resin rigidified fiberglass mat. Furthermore, the vane or slatis suitable for use in a vertical covering. When used in a verticalcovering will not “barber pole” or twist along its length so that whenthe vane is rotated at its upper end by a control system, the lower endwill rotate in unison therewith. The material from which the slat orvane is manufactured is important to its functionality and through useof glass fibers and a thermosetting resin, the vane can be formed tohave deformation memory whereby it will retain its tubular orientationunder normal circumstances but can be deformed by compressing, foldingor the like and will rebound to its original configuration due to thememory provided therein with the glass fibers and the thermoformableresin. The slat or vane so formed is thereby resilient and can bedeformed repeatedly without losing the ability to return to its originalconfiguration. This resiliency allows the slats to be compressed asshown in FIG. 12 when an associated blind assembly is retracted, andreturn to there undeformed configuration when the blind assembly islowered.

Although the present invention has been described with a certain degreeof particularity, it is understood that the present disclosure has beenmade by way of example, and changes in detail or structure may be madewithout departing from the spirit of the invention as defined in theappended claims.

1. A method of forming an elongated flat strip of material into anelongated strip having an arcuate transverse configuration, manipulatingthe strip into a roll such that the arcuate transverse configuration isflattened and subsequently unrolling the flattened strip so it reassumesan arcuate transverse configuration, comprising the steps of: providingan elongated starter strip of fiberglass in a thermosetting resin thathas not been cross-linked by being heated; providing a first stationarymandrel having an arcuate surface and a system for heating said firststationary mandrel; providing a second stationary mandrel having anarcuate surface and a system for cooling said second stationary mandrel;passing said starter strip along its length across said first stationarymandrel to heat said thermosetting resin above its setting temperatureto form a heated strip having said transverse arcuate shape; passingsaid heated strip along its length across said second stationary mandrelto cool said thermosetting resin beneath its setting temperature to forma cooled strip having said transverse arcuate shape; rolling up saidcooled strip, whereby it will become deformed into a flattenedtransverse configuration and unrolling said deformed flattened stripallowing it to re-assume said arcuate transverse cross-section.
 2. Themethod of claim 1, further including the steps of providing an elongatedstrip of fabric adjacent to said elongated starter strip, applyingadhesive to one of said strips, and bonding said strips together into alaminate before passing said starter strip across said stationarymandrels.
 3. The method of claim 1 or 2 wherein said arcuate surfaces ofsaid stationary mandrels are convex.
 4. The method of claim 3 furtherincluding the steps of providing mandrel components having a concavearcuate surface to complement said convex arcuate surfaces of saidstationary mandrels and placing said mandrel components in confrontingrelationship with said stationary mandrels such that an arcuate space isdefined therebetween through which said starter strip can be passed. 5.The method of claim 1 or 2 wherein said starter strip is provided inroll form.
 6. The method of claim 2 wherein said starter strips and saidstrip of fabric are provided in roll form.
 7. The method of claim 1wherein said starter strip contains 21 to 24% by dry weight of athermosetting resin.